The paper moves by conveyor ti a big vat called a pulper, which contains water and chemicals. The pulper chops the recovered paper into small pieces. Heating the mixture breaks the paper down more quickly into tiny strands of cellulose (organic plant material) called fibers. Eventually, the old peper turns into a mushy mixture called pulp. The pulp is forced through screens containing holes and slots of various shapes and size. The screens remove small contaminants such as bits of plastic and globs of glue. This process is called screening